Telephone-exchange system



H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION mmszPT; I4, 1911 1,3373% Patented Apr. 20,1920,

UNITED STATES PATENT OFFICE.

HENRY PETER CLAUSEN, OF MOUNT VERNON, YORK, ASSIGNOR TO WESTERN ELECTRIC CQMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEVJ YORK.

TELEPHGIIE-EXCHANGE AppIication filed September 14, 1917.

To all whom it may concern:

Be-it known that I, HENRY P. CLAUSEN, a citizen of the United States, residing at Mount Vernon, in the county of lVestchester and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact de scription.

This invention relates to telephone er:-

change systems, and more particularly to such systems of the central energy type.

An object of this invention is to provide improved means for connecting an operators telephone set with a link circuit employed for connectin telephone lines together for conversation. Another object of this invention is to provide improved signaling means for central energy telephone systems.

In accordance with a feature of this invention, a link circuit employed for interconnecting telephone lines for conversation is provided with a relay for automatically controlling the connection and disconnection of an operators telephone set with the link circuit, and with a manually controlled switch for connecting the operators telephone set with the link circuit. The relay and the switch cooperate in such a manner that, when only the answering end of the link circuit is connected with the telephone line, the relay is energized to connect the 'operators telephone set with the link circuit through normally closed contacts of the switch, and, when both ends of the link circuit are connected with telephone lines, the actuation of the switch connects the operators telephone set with the link circuit through normally closed contacts of the relay. In accordance with another feature or" this invention, means are provided for causing a signaling device to furnish a characteristic signal when the listening switch of a link circuit oining two telephone lines is actuated. In accordance with another feature of this invention, a link circuit is provided with apparatus, by means of which, when the calling end thereof is connected with a telephone line as a called line and the answering end is not connected with a line and the called line responds, a circuit is,

completed through a signaling device for causing the signallng devlce to furnish a characteristic signal lndlcatlng that an act Specification of Letters Patent.

Patented Apr. 20, 1920.

Serial. No. 191,373.

upon the part of the operator is required in establishing a connection.

For a more complete understanding of this invention, reference should be had to the toll wing description considered in connection with the accompanying drawing illustrating one embodiment of this invention.

In tne drawing there is shown a poly-station telephone line A, terminating at a central oiiice, and a sin le party telephone line B, also termirnating at the same central oihce. At the central otlice, there is provided a cord circuit C, employed for interconnecting telephone lines. It is to be understood that a number of lines, similar to lines A and B, may terminate at the same central oi'lice, and that a number of cord circults, similar to C, may be provided thereat for interconnecting the lines. For convenience, however, only the two lines and the one cord circuit are shown. It is thought that this invention will be clearly understood from a description of the operation of the system shown in the drawing, and it will be so described.

One of the subscribers on the party line A in initiating a call, removes the receiver from the switchhook, thereby causing the operation of line relay 5, whereupon line lamp 6 is lighted. The operator, upon observing the lighted condition of line lamp 6, inserts answering plug 7 of the cord circuit G into one of the jacks, for example 8, thereby causing the operation of relay 9 and cutoff relay 10 over a circuit from battery through the winding or" relay 9, sleeve contacts of answering plug 7 and jack 8, and the winding or" cutoff relay. 10 to ground. Cutofl? relay 10, in 01 erating, disconnects the line relay from the line, and thereby extinguishes the line lamp 6. Relay 9, in operating, merely opens its contacts. Answering supervisory lamp 11 would now be lighted through the normal contact of supervisory relay 12 and the sleeve contacts of the plug and jack, were it not for the fact that supervisory relay 19 is energized upon the con nection of answering plug 7 with the jack 8. Upon the energization of the supervisory relay 12, the short-circuit about resistance 13 is opened, thereby including the resistance in circuit with the lamp and preventing the lighting thereof. Upon the insertion of plug 7 into jack 8, listening relay 15 is energized over a circuit from battery through the normal contact of relay 16, winding of listening relay 15, sleeve contacts oi the answering plug 7 and jack 8, and the winding of cutofi' relay 10 to ground. Relay 15, in operating, connects an operators telephone set with the talking strands of the cord circuit C by way of the normally closed contacts of listening key 17 and the alternate contacts of the listening relay 15. The operator is now connected with the talking strands of the cord circuit and may converse with the calling subscriber. It, while listening relay 15 is actuated, the operator desires to answer another call, the actuation of listening key 17 disconnects the operators telephone set from the talking strands of the cord circuit C, so that the operator may then insert an answering plug of another cord circuit into the jack of another calling line, whereupon the telephone set is connected with the second calling line. After completing a connection for this second calling subscriber, the operator may restore listening key 17 to normal position, again connecting the telephone set with the cord circuit C. 1

Upon being advised by the calling subscriber that connection is desired with line B, the operator inserts calling plug 20 into jack 21, whereupon relay 16 and cutoff relay are operated, and calling supervisory lamp 23 is lighted. The operation of relay 16 opens the circuit of listening relay 15, causing its deenergization and the consequent disconnection of theoperators telephone set from the cord circuit C. In order to signal the subscriber of line B, the operator may momentarily actuate key 24, thereby causing the operation of relay 25 over a circuit from battery through the alternate contact of relay 16, right-hand alternate contact of supervisory relay 12, winding of relay 25, and the contact of key 24 to ground. The relay 25, in operating, substitutes its middle alternate contact for the contact of key 24, whereby relay 25 is locked up through its middle alternate contact and the contact of tripping relay 26. The operation of relay 25 opens the tip talking strand of the cord circuit C and connects ringing current with the called line B over a circuit from the source of ringing current 27 through the winding of tripping relay 26, upper alternate contact of ringing relay 25, tip contacts of the plug 20 and jack 21, through call bell 28 and condenser 29 at the subscribers station line B, ring contacts of the jack 21 and plug 20, the lower alternate contact of ringing relay 25, resistance 30, and battery to ground. The called subscriber, in responding to the operation of the call bell 28, removes the receiver from the switchhook, thereby establishing a low resistance path for ringing current. Tripping relay 26 is thereby energized to open its contact in the locking circuit of ringing relay 25, which then releases, disconnecting the source of ringing current from the called line. Upon the release of ringing relay 25, the break in the tip conductor of the cord circuit C is closed, and calling supervisory relay 32 is thereupon operated to remove the shortcircuit from resistance 33, which is thereupon included in circuit with the calling supervisory lamp 23 to extinguish the lamp.

If, while the two lines A and B are connected by means of, the cord circuit C, the operator wishes to listen-in on the connection to properly supervise it, the actuation of listening switch 17 immediately connects the operators telephone set to the talking strands of the cord circuit through alternate contacts of the listening switch 17 and normal contacts of the listening relay 15. Under such condition, that is, while the calling line A and the called line B are connected by the cord circuit C, and the listening switch 17 is actuated, the answering supervisory lamp 11 is intermittently lighted over a circuit from battery through lamp 11, left-hand alternate contact of supervisory relay 12, resistance 3%, lower normal contact or listening relay 15, the right-hand alternate contact of listening switch 17, and interrupter 35 to ground.

The intermittent lowin of the answer-in D D D supervisory lamp 11 is a signal to the oper-,

ator that the telephone set is connected with an established connection between two subscribers lines. The restoration of the listening switch 17 to normal position dis connects the operators telephone set from the talking circuit and stops the intermittent glowing of answering supervisory lamp 11.

At the conclusion or the conversation, the subscribers restore the receivers to the switchhooks, causing the release of the supervisory relays 12 and 32, whereupon the supervisory lamps 11 and 23 are lighted to furnish disconnect signals. The operator may thereupon withdraw the plugs from the jacks, permitting all apparatus to be restored to normal condition.

When answering a call and conversing with the calling subscriber, if the operator is advised that the station desired is on the same line with the calling subscriber, it is the usual practice for the operator to request the calling subscriber to restore the receiver to the switchhook, so that the ope erator may signal'the desired subscriber on that line. The operator then withdraws the answering plug from the jaclrandinserts the calling plug 20 into one of the jacks of line A, for example jack 40, and momentarily actuates key 2% in the manner hereinbefore described, thereby to cause the operation and locking up of ringing relay 25. The energizing and locking circuits for ringing relay 25, when the answering plug 7 is not inserted in a jack, include the left-hand normal contact of relay 9 instead of the right-hand alternate contact of supervisory relay 12. Upon the operation of the ringing relay 25, ringing current is connected with the line. In response to the operation of the call bell, the called subscriber on the line, and probablythe calling subscriber on the line, may remove the receiver from the switchhook, whereupon tripping relay 26 operates and ringing relay 25 releases. Supervisory relay 32 is thereupon operated, and, in operating, causes supervisory lamp 23 to glow intermittently to furnish a characteristic signal to the operator that the called subscriber has answered, and that she should supervise the connection to determine whether the calling subscriber is now on the line. The operating circuit for the lamp 23 may be traced from battery through lamp 23, alternate contact of supervisory relay 82, resistance 89, right-hand normal contact of relay 9, and interrupter 4:1 to ground. The operator, observing the flashing of the lamp 23, may now actuate listening switch 17, connecting the operators telephone set to the line for the purpose of supervision. Lamp 23, however, will continue to glow in termittently until the operator inserts the answering plug 7 into another jack, either of that line or into a jack associated with some other line. It is preferable, however, to connect the answering plug 7 with a jack of line A, so that extra talking current may be furnished for the operation of the two transmitters which will be bridged across the same line. The insert-ion of the plug 7 in a jack of line A causes the operation of relay 9, which attracts its armatures, thereby effacing the supervisory lamp 23. The answering supervisory lamp 11 is not lighted upon the connection of plug 7 with a jack of line A for supervisory relay 12 is immediately operated. At the conclusion of the conversation, the subscribers restore the receivers to the switchhooks, causing the release of the supervisory relays and the light ing of the lamps, whereby the operators may withdraw the plugs from the jacks, restoring all apparatus to normal condition.

hat is claimed is:

1. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, an operators telephone set, a relay in the link circuit energized due to the connection of one end of the link circuit with a telephone line to connect the operators telephone set with the link circuit, means operated in response to the connection of the other end of the link circuit with another telephone line to cause the deenergization of said relay and the disconnection of the operators telephone set from the link circuit, and a manually operated switch adapted when actuated to connect the operators telephone set with the link circuit through normally closed contacts of said relay.

2. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, a manually operated switch and a relay associated with the link circuit, an operators telephone set and circuit leads for connecting the operators telephone set with the link circuit through normally closed contacts of the switch and contacts of the relay when energized, and through normally closed contacts of the re lay and contacts of the switch when actuated.

3. A telephone exchange system comprising telephone lines, a link circuit adapted to be connected with two of the lines, an operators telephone set, a relay in the link circuit energized upon the connection of one end of the link circuit with the line to connect the operators telephone set thereto, a relay energized upon the connection of the other end of the link circuit with a line for causing the denergization of the first relay, and a manually operated switching device subsequently actuated to connect the operators telephone set with both ends of the link circuit through normally closed contacts of the first relay.

4. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, an operators telephone set, a listening switch, a relay energized upon connection of one end of the link circuit with one of the telephone lines to connect the operators telephone set to the link circuit through normally closed contacts of the listening switch, electromagnetic switching mechanism responsive to the connection of the other end of the link circuit with another telephone line to cause the disconnection of the operators telephone set from the link circuit, and circuitleads for con necting the operators telephone set to the link circuit through normally closed contacts of the first mentioned relay upon the subsequent actuation of the listening switch.

5. A telephone exchange system comprising two telephone lines, a link circuit joining the two lines together as calling and called lines, an operators telephone set, a switching device for connecting the operators telephone set with the link circuit, a supervisory relay in the link circuit controlled from the calling line, a signaling device, and an operating circuit for the signaling device including a contact of the supervisory relay completed upon the actuation of the switching device while the supervisory relay is energized.

6. A telephone exchange system comprising two telephone lines, a link circuit joining the two'lines together as calling and called lines, an operators telephone set, a switching device for connecting the operators telephone set with the link circuit, a supervisory relay in the link circuit controlled from the calling line, a signaling device, interrupter mechanism, an operating circuit for the signaling device, and interrupter mechanism included in the operating circuit upon the actuation of the switching device for causing the intermittent operation of the signaling device while the super visory relay is energized. f

7. A telephone exchange system comprising telephone lines, a link circuit for interconnecting the lines, an operators telephone set, a relay energized upon the connection of one end of the link circuit with one of the lines to connect the operators telephone set therewith through normally closed contacts of the listening switch, a relay energized upon the connection of the other end of the link circuit with another of the lines to cause the disconnection of the operators telephone set from the link circuit, a signaling device, interrupter mechanism, an operating circuit for the signaling device and the interrupter mechanism including a contact ot' the first mentioned relay completed by the actuation of the listening switch, and circuit connections for connecting the operators telephone set with the link circuit upon actuation of the listening switch.

8. A telephone exchange system comprising a telephone line terminating in a plurality of sets of switching terminals, a link circuit connected with one set of the switching terminals, asupervisory relay in the link circuit and controlled over the connected line, a signaling device, interrupter mechanism brought into the circuit with the signaling device upon the energization of the supervisory relay for causing the intermittent operation of the signaling device, and

a relay actuated upon connection of the link circuit with another set of switching terminals to stop the intermittent operation of the signaling device. '7

In witness whereof, I hereunto subscribe my name this 8th day of September, A. D.

HENRY PETER OLAUSEN. 

